The invention relates, in general, to an apparatus and method for forming an occlusion in a mammalian body, and, in particular, to an apparatus and method for embolizing an aneurysm with a magnetically controllable substance.
Like all parts of the body, the brain is composed of living cells that require a blood supply to provide oxygen and nutrients. A hemorrhage in a blood vessel in the brain or in the space closely surrounding the brain is a common cause of strokes. Hemorrhage refers to bleeding into the brain, usually because of a problem with a blood vessel. The problem is often an aneurysm.
An aneurysm is an abnormal bulging outward of blood vessel wall. The wall may smoothly bulge outward in all directions (a fusiform aneurysm) or it may form a sack arising from one wall (a saccular aneurysm). If the aneurysm ruptures, a hemorrhage occurs. This can compress and irritate the surrounding blood vessels, resulting in a reduced supply of oxygen and nutrients to the cells, possibly causing a stroke.
Aneurysms can be treated from outside the blood vessel using surgical techniques or from inside the blood vessel using endovascular techniques. Endovascular treatment of an aneurysm is performed using a catheter. X-ray, magnetic resonance imaging (MRI) equipment, or other visualization equipment may be used to view the progress during the procedure.
A magnetically directable embolic such as an acrylic, iron-containing glue has been proposed to fill or obliterate aneurysms. The embolic is delivered by means of a catheter and is directed into an aneurysm with an external magnetic field generated by a permanent magnet or electrogmanetic device used for Stereotaxis prcedures such as a prototype device made by Stereotaxis Inc. of St. Louis, Mo. An example of such a device is shown and described in U.S. Pat. No. 6,014,580 to Blume, et al. Problems with this approach include that the Stereotaxis machine is cumbersome and expensive and, in some cases, the external magnetic field produced by the Stereotaxis machine is not strong enough to control delivery of the iron-containing, magnetically-directable glue into the aneurysm.
An aspect of the present invention involves a magnetic embolization apparatus for embolizing an aneurysm of a blood vessel. The magnetic embolization apparatus includes a catheter with a distal portion, and a permanent magnet and an electromagnet carried by the distal portion to internally induce a magnetic field in the aneurysm to control a magnetic field controllable embolic to embolize the aneurysm.
Implementations of the aspect of the invention described immediately above may include one or more of the following. The electromagnet is adapted to induce a magnetic field in a first direction to strengthen a magnetic field induced by the permanent magnet to embolize the aneurysm and in a second direction to counteract the magnetic field induced by the permanent magnet to assist in withdrawing the catheter from the aneurysm without removing any embolic. The distal portion includes a sealed tip to prevent a magnetic field controllable embolic from being drawn into the catheter. The permanent magnet is located circumferentially outside or inside the electromagnet. The catheter includes a wall with the permanent magnet and electromagnet located therein. A guide wire is slidably disposed in the catheter and carries the permanent magnet. The catheter includes a lumen that carries the permanent magnet.
Another aspect of the invention involves a method of embolizing an aneurysm of a blood vessel. The method includes delivering a magnetic-field controllable embolic into an aneurysm, and simultaneously inducing a magnetic field in the aneurysm with a permanent magnet and an electromagnet to embolize the aneurysm.
Implementations of the aspect of the invention described immediately above may include one or more of the following. A catheter includes a distal portion with the permanent magnet and the electromagnet located therein, and the step of simultaneously inducing a magnetic field in the aneurysm includes simultaneously inducing a magnetic field in the aneurysm with the permanent magnet and the electromagnet of the catheter to induce the magnetic filed in the aneurysm. The method further includes the steps of using the electromagnet to induce a magnetic field in a first direction to strengthen a magnetic field induced by the permanent magnet to embolize the aneurysm and in a second direction to counteract the magnetic field induced by the permanent magnet to assist in withdrawing the catheter from the aneurysm without removing any embolic. A guide wire is slidably disposed in the catheter and carries the permanent magnet, and the method further includes the step of introducing the permanent magnet into the aneurysm with the guide wire. The step of delivering a magnetic-field controllable embolic into the aneurysm is done with a second, separate microcatheter.
Other features and advantages of the invention will be evident from reading the following detailed description, which is intended to illustrate, but not limit, the invention.